Driver for optical deflector using two asyncronous saw-tooth drive voltages and method for setting the same

A method for setting drive data for driving an optical deflector which comprises:

• a mirror;
• a movable frame for supporting said mirror;
• a support body surrounding said movable frame;
• and
• a first group of piezoelectric actuators serving as cantilevers and a second group of piezoelectric actuators serving as cantilevers alternating with said first group of piezoelectric actuators, wherein said piezoelectric actuators are folded at every actuator and connected from said support body to said movable frame, each of said piezoelectric actuators being in parallel with one axis of said mirror,
• said method comprising:
• setting a period common to first and second drive voltages for said first and second groups of piezoelectric actuators, respectively;
• designating a ratio of a rising period to a falling period, a total of said rising period and said falling period being equal to said set period to select first drive data for said first group of piezoelectric actuators forming a saw-tooth wave having said rising period and said falling period;
• and
• inverting and shifting said first drive data to obtain second drive data for said second group of piezoelectric actuators,
• wherein a shifted amount of said first drive data is a value corresponding to a half wave-length of a natural frequency of a mechanically-vibrating system of said mirror with respect to said axis thereof depending upon said piezoelectric actuators.